children(2) symptom onset(1) SARS-COV-2 infection(1) viral infections(1) long-COVID syndrome(1) syndrome(1) diagnostic(1) motif(1) hyperventilation(1) RT-qPCR(1) bandwidth(1) adverse effects(1) Patient(1) Course(1) glycoprotein(1) Antibody testing(1) applied(1) Blood(1) S-gene(1) spike(1) Biomarkers(1) gold standard(1) Genome(1) pediatric transplantation(1) heterogeneous(1) MIS-C(1) SARS-CoV-2 B.1.1.7(1) Functional respiratory disorder(1) subgenomic RNA(1) Combined(1)